Vitamin-D Boosted Marinated Mushroom

When I was little my grandmother always took us kids mushroom picking in the dark mysterious Swedish woods.
She could name every mushroom we came across and she knew exactly where they were hiding,
I wish I had paid more attention.
Here in London I do my mushroom picking at err.. Whole Foods, where they have an amazing selection at the moment.
For this recipe I think chestnut buttons work best.
And remember to let your mushrooms sun bathe to boost that all important Vitamin D!